Clinicians and researchers have sought to describe and define a personality type that shares some characteristics of schizophrenia as stable personality traits and shares a common genetic substrate. DSM-III consolidated these efforts by including Schizotypal Personality Disorder (SPD). Much work on SPD has focused on the association of various symptoms with the diagnosis. The proposed study will determine if cognitive and psychophysiological measures related to schizophrenia support the validity of SPD and evaluate the discriminative validity of the individual criteria. Because there is some evidence that SPD may identify a heterogeneous group, the study will also test a putative distinction between two types of SPD, one genetically related to schizophrenia (familial SPD) and another that is not (clinical SPD). The study will also serve as a field trial for proposed DSM-IV criteria. There will be two SPD subgroups with 30 in each subgroup: (1) first- degree relatives of schizophrenic probands (FSPDs); and (2) outpatient SPDs without schizophrenic relatives (CSPDs). There will be four non-SPD comparison groups (n=30 in each): (1) non-SPD first-degree relatives of schizophrenic probands; (2) non-SPD first-degree relatives of non- schizophrenic psychotic probands; (3) outpatients with non-SPD personality disorders; (4) outpatients and relatives with borderline personality disorders at the Brockton V.A. and an outpatient clinic at McLean Hospital. Groups will be compared on symptomatology and vulnerability markers (Smooth Pursuit Eye Movement, Wisconsin Card Sorting Test, Continuous Performance Test, Span of Apprehension, Visual Verbal Test, and Verbal and Nonverbal Cancellation Test). Some comparisons will contrast the entire SPD sample (n=60) to the entire comparison sample (n=120), while other comparisons will compare SPD subgroups (i.e., CSPDs and FSPDs) to one another and to specific non-SPD comparison groups. The inclusion of "endophenotypes", such as psychophysiological and neuropsychological functions, that may be associated with schizophrenia, but be causally "closer" to the genotype, may help explicate the relationship of SPD, or some subset of SPD, to schizophrenia.